1. Field of the Invention
The present invention pertains generally to wrenches used to unfasten polygonal nuts recessed into an axle hub and more specifically relates to such a wrench that engages only one facet of said polygonal axle nut and is actuated by rotation of an associated wheel.
2. Background of the Prior Art
It is old in the art to completely encase a polygonal nut in a thin wall socket and apply torque to the center of the socket to remove the nut. Sockets of this type break easily because of their thin wall construction. Further, a large number of varying size sockets must be bought and stored to accomodate the different sizes of nuts used on commercial vehicles.
Wrenches constructed according to the general concept of the present invention are also well-known. U.S. Pat. No. 2,512,978 teaches such a wrench as does U.S. Pat. No. 3,295,399, which is incorporated herein by reference. All wrenches taught by the prior art suffer from disadvantages. Prior art wrenches can accomodate only specific sizes of nuts and will operate properly only if the nut is at a particular distance within a wheel hub. Additionally, prior art wrench designs teach that the slidably disposed member must be locked in rigid orthogonal alignment with its cross-member to operate properly. Such wrenches are extremely difficult to store or carry conveniently and are very heavy. Further, this orthogonal fixed alignment will not allow the wrench to adapt to all types of hubs. For practical reasons no prior art wrench of the type taught by the present invention has achieved commercial success.
In addition to structural deficiencies of present and all prior art wrenches, no prior art wrench could function without ruining the associated hub's wheel lugs. This type of wrench must be made of tool steel to be tough enough to remove a tightly screwed on nut without ruining or deforming. Tool steel is much harder than mild steel used to make threaded lugs such as the lugs that strike the wrench. In normal operation, threaded lugs impinge upon the upper surface of one arm of the wrench with considerable force. This force does not harm the tool, but does deform threads on the lug. This ruins the lug. It will readily be appreciated that this practical drawback prevents prior art wrenches from achieving commercial success.
It is an object of the present invention to provide a tool that is lighter and simpler than prior designs while retaining all their advantages.
It is a further purpose of the present invention to provide a tool whose longitudinal members are slidably and rotatably affixed to one another so the tool may be collapsed for storage and adapt to all hub designs.
Yet still another purpose of the present invention is to provide a tool that operates without ruining threads on the striking lug used to actuate the tool.
Yet still a further purpose of the present invention is to provide a tool capable of demounting a large number of different sizes of hub nuts regardless of their disposition within the hub.